How do I make a video of what's happening on my screen?

I want an application which is a movie version of the Screenshot application. In other words, rather than take a single image of the screen at a given instant, it makes a movie of what's happening on the screen over some duration. Can OpenShot do that? If it can, then can you please explain how. If not, then which app should I use?

I'm using Ubuntu 15.04 and will most likely upgrade very soon after 15.10 comes out.